I just got a CD in the mail from Cessna with G1000 installation software. The file on the CD is 006-B0563-21_0A.exe and it appears to be an update to 0563.21 -- when I turn on the MFD, I see version 563.21. This is a new plane (2011 T182T) and I'm still new to plane ownership, so please excuse me if this is a stupid question - I searched around but couldn't find anything.

a) Am I correct in assuming I already have this version? Or is there actually a 563.21 "0A" or something of the sort?
b) Is this normal to get a CD out of the blue with no accompanying explanation / letter?
c) Were it actually a newer version, is this something that is owner updateable, or does the pfd/mfd software have to be updated by a garmin authorized entity?